It is the purpose of this invention to provide a mechanism for securely retaining sockets or other tool attachments on, and easily releasing them from, socket wrenches. The mechanism of this invention can generally be used on all hand-held tools, including power and impact tools having removable sockets or other tool attachments and in particular can be used with hand-held socket ratchet wrenches.
Socket wrenches of the type referred to herein have a handle, a head, and a square or hexagonal (or the like) drive stud or tang for receiving removable sockets or other tool attachments. For many years prior to the invention of the first quick-release mechanism for socket wrenches as disclosed in U.S. Pat. No. 3,208,318 (Roberts), the removable sockets were usually secured to the wrench with a conventional ball detent mechanism.
In the conventional ball detent design, the ball detent is spring mounted in an aperture in the drive stud with the normal position of the ball detent being in an outward position, that is, with the ball projecting outward of the surface of the drive stud. When the socket is mounted on the drive stud, the spring loaded detent protrudes from the exterior surface of the drive stud to engage a recess in the socket and thereby hold the socket onto the drive stud. To remove the socket from this conventional ball detent design stud, the user normally grasps the socket with his hand and exerts a force on it by pulling it, thereby forcing the spring loaded ball detent to recede into the aperture so that the socket can be pulled or pried off and released from the drive stud.
This conventional manner of securing and releasing sockets, however, resulted in a great many practical difficulties. One of these problems was that the removal of the socket required the use of both of the user's hands: one hand to hold the handle of the wrench and the other hand to pull the socket off the drive stud. Removal of the socket in this manner became a particularly time-consuming and labor wasting task, especially when the socket or the user's hands became greasy and it consequently became difficult for the user to grasp and hold the socket while pulling on it. This problem was exacerbated by the stiff spring necessarily present in a new wrench if the spring was to exert a force sufficient to retain a socket or other attachment through the expected life of the wrench.
Moreover, removal of this socket proved difficult or impossible if the conventional ball detent spring mechanism jammed, as it sometimes did when it became contaminated with dirt or grease, both of which are, of course, ordinarily present in the working places of mechanics who frequently use such tools. The consequence of such contamination was that a great deal of force was ordinarily required to remove the socket.
As a makeshift remedy for these problems, users frequently removed the socket from the wrench by prying it off with a screwdriver or other levering device. Indeed, the problem became so acute that some manufacturers offered special tools to pry off sockets. This time-consuming procedure of removing sockets from wrenches became particularly troublesome for commercial mechanics, who frequently use such wrenches for many hours during the day and change sockets many times during that period.
Prior to the instant invention, the first and only fully effective solution to this problem is provided in the "quick-release" mechanism shown in the above-referred to Roberts' patent. As shown in that patent (FIG. 1, 2, 3, 4), an elongate longitudinal passage in the drive stud receives an elongate slideable pin, one end extending through the top of the head of the wrench and secured to a control knob and the other end substantially flush during normal operation with the bottom face of the drive stud. The drive stud has an aperture for receiving a ball detent, the edges of the aperture preventing the ball detent from passing outside of the stud.
A coil spring mounted in a section of said longitudinal passage maintains the pin normally in a position to keep the ball detent in an outward position, the ball detent thereby normally engaging and securely holding the socket. The slideable elongate pin is provided with a recess, so that when the operating button is depressed, the pin moves longitudinally in the passage until the detent is received in the recess. At that point, the socket is no longer secured to the drive stud and can be permitted to drop off through the force of gravity.
The above-described invention proved to be a remarkable success that was quickly adopted in most conventional socket wrenches and virtually revolutionalized the socket wrench field. For the first time any user of socket wrenches could easily and swiftly remove sockets from socket wrenches and replace sockets back on the drive stud with little effort, and while using only one hand. One-handed operation was a decided time and cost advantage when, for example, a mechanic needed one hand to change a socket while holding a part he was working on in place with the other hand. Today, a large percentage of all socket wrenches in use are provided with some mechanism to facilitate the release of sockets from wrenches.
Roberts' quick-release mechanism, however, did not provide for positive locking of the socket onto the drive stud to prevent accidental release of the socket. This added feature would be highly useful on power and impact tools and also on socket wrenches when, for example, work is being done on bridges or high buildings or the like where the accidental loss of a socket by unintended release can also be very dangerous to valuable or delicate machinery or property below and even to life.
There are numerous other circumstances where a positive locking mechanism would be highly desirable. For example, in using socket wrenches in repetitive tasks requiring prolonged use of the same tool attachment, a positively locking mechanism is highly desirable. In another circumstance, it is sometimes necessary to employ what is referred to as an extension bar to facilitate the removal of bolts that would otherwise not be accessible to a mechanic. An extension bar is ordinarily secured to the drive stud of the wrench, as is any regular socket; the other end of the extension bar is provided with a similar drive stud for receiving a socket. Ordinarily, the socket is retained and released from the extension bar drive stud with a conventional ball detent mechanism of the kind described above.
When a user needs to remove a socket from the extension bar, he simply pulls it off. But in doing so, it is imperative that he not also remove the extension bar from the wrench drive stud which would often happen in a conventionally designed ball detent mechanism; to do so would be frustrating and time consuming, requiring a three-hand operation. The incorporation of a locking mechanism onto the socket wrench to securely lock the extension bar onto the drive stud alleviates this problem.
There is therefore a need in the field for an inexpensive, reliable, and easy to construct mechanism for socket wrenches that permits the rapid release and retention of sockets during normal, or "quick-release" operation, and also permits the user to positively lock the socket onto the drive stud of the wrench in a "positively locked" mode in order to preclude the possibility of accidental release of the socket.